The testusb program just issues ioctls to perform the tests
implemented by the kernel driver. It can generate a variety
of transfer patterns; you should make sure to test both regular
streaming and mixes of transfer sizes (including short transfers).

For more information on how this can be used and on USB testing
refer to <URL:http://www.linux-usb.org/usbtest/>.

The Function Filesystem (FunctioFS) lets one create USB
composite functions in user space in the same way as GadgetFS
lets one create USB gadgets in user space. This allows
creation of composite gadgets such that some of the functions
are implemented in kernel space (for instance Ethernet, serial
or mass storage) and other are implemented in user space.

The FunctionFS is a USB composite function that can be used
with the composite framework to create an USB gadget.

>From kernel point of view it is just a composite function with
some unique behaviour. It may be added to an USB
configuration only after the user space driver has registered
by writing descriptors and strings (the user space program has
to provide the same information that kernel level composite
functions provide when they are added to the configuration).

>From user space point of view it is a file system which when
mounted provide an "ep0" file. User space driver need to
write descriptors and strings to that file. It does not need
to worry about endpoints, interfaces or strings numbers but
simply provide descriptors such as if the function was the
only one (endpoints and strings numbers starting from one and
interface numbers starting from core). The FunctionFS changes
numbers of those as needed also handling situation when
numbers differ in different configurations.

When descriptors and strings are written "ep#" files appear
(one for each declared endpoint) which handle communication on
a single endpoint. Again, FunctionFS takes care of the real
numbers and changing of the configuration (which means that
"ep1" file may be really mapped to (say) endpoint 3 (and when
configuration changes to (say) endpoint 2)). "ep0" is used
for receiving events and handling setup requests.

New wait_event_interruptible{,_exclusive}_locked{,_irq} macros added.
They work just like versions without _locked* suffix but require the
wait queue's lock to be held. Also __wake_up_locked() is now exported
as to pair it with the above macros.

The use case of this new facility is when one uses wait queue's lock
to protect a data structure. This may be advantageous if the
structure needs to be protected by a spinlock anyway. In particular,
with additional spinlock the following code has to be used to wait
for a condition:

Reimplement fifo-based writes in the generic driver using a multiple
pre-allocated urb scheme.

In contrast to multi-urb writes, no allocations (of urbs or buffers) are
made during run-time and there is less pressure on the host stack
queues as currently only two urbs are used (implementation is generic
and can handle more than two urbs as well, though).

Initial tests using ftdi_sio show that the implementation achieves the
same (maximum) throughput at high baudrates as multi-urb writes. The CPU
usage is much lower than for multi-urb writes for small write requests
and only slightly higher for large (e.g. 2k) requests (due to extra copy
via fifo?).

Also outperforms multi-urb writes for small write requests on an
embedded arm-9 system, where multi-urb writes are CPU-bound at high
baudrates (perf reveals that a lot of time is spent in the host stack
enqueue function -- could perhaps be a bug as well).

Keeping the original write_urb, buffer and flag for now as there are
other drivers depending on them.

Note that this will also make it fairly easy to use the generic
fifo-based write implementation: simply unset the multi_urb_write flag
and modify prepare_write_buffer (or unset if not using a legacy SIO
device). This may be desirable for instance on an embedded system where
optimal throughput at high baudrates may not be as important as other
factors (e.g. no allocations during runtime and less pressure on host
stack).

This USB video class function driver implements a video capture device from the
host's point of view. It creates a V4L2 output device on the gadget's side to
transfer data from a userspace application over USB.

The UVC-specific descriptors are passed by the gadget driver to the UVC
function driver, making them completely configurable without any modification
to the function's driver code.

Change the type of the URB's 'sg' pointer from a usb_sg_request to
a scatterlist. This allows drivers to submit scatter-gather lists
without using the usb_sg_wait() interface. It has the added benefit
of removing the typecasts that were added as part of patch as1368 (and
slightly decreasing the number of pointer dereferences).

These Appotech controllers are found in Picture Frames, they provide a
(buggy) emulation of a cdrom drive which contains the windows software
Uploading of pictures happens over the corresponding /dev/sg device.

When a device is disconnected, xhci_free_virt_device() is called. Ramya
found that if the device had streams enabled, and then the driver freed
the streams with a call to usb_free_streams(), then about a minute after
he had called this, his machine crashed with a Bad DMA error. It turns
out that xhci_free_virt_device() would attempt to free the endpoint's
stream_info data structure if it wasn't NULL, and the free streams
function was not setting it to NULL after freeing it.

This patch (as1375) eliminates the usb_host_ss_ep_comp structure used
for storing a dynamically-allocated copy of the SuperSpeed endpoint
companion descriptor. The SuperSpeed descriptor is placed directly in
the usb_host_endpoint structure, alongside the standard endpoint
descriptor.

Fix mos7720 Kconfig dependencies.
When an enabled bool selects a tristate, the tristate becomes =y,
even if it should be limited to modular, so limit the bool kconfig
option to configs that will build cleanly.
Also change the if-block to a simple depends on.

No functionality added or bugs fixed, just improved code consistency and
(hopefully) readability by replacing send_mos_cmd with the register read & write
functions that were used for parallel port registers. Also shortens overall
file length.

Thoroughly tested, with emphasis on regression testing the serial port.

Add support for the parallel port on the moschip MCS7715 device. The port
registers itself with the parport subsystem as a low-level driver. A separate
entry to the kernel configuration is added beneath that for the mos7720, to
avoid the need to link with the parport subsystem code for users who don't have
or don't want the parallel port. Only compatibility mode is currently supported
(no ECP/EPP). Tested with both moschip devices (7720 and 7715) on UP and SMP
hosts, including regression testing of serial port, concurrent operation of
serial and parallel ports, and various connect / disconnect scenarios.

I've been running with this patch on my Niagara2 boxes for some time
and have not seen any ill effects yet. Maybe we can stash this into
the USB tree to get exposure for some time in -next and if anything
crops up we can simply revert?

It seems unlikely that this entry is needed anymore since the kernel
has logic to handle devices that poorly respond to INQUIRY. Since we
now have another entry with the same VID/PID but different flags, it's
a good time to attempt to clean this up.

The original submitter's email no longer works, so we'll keep an eye
out for any regression reports.

Bulk endpoint streams were added in the USB 3.0 specification. Streams
allow a device driver to overload a bulk endpoint so that multiple
transfers can be queued at once.

The device then decides which transfer it wants to work on first, and can
queue part of a transfer before it switches to a new stream. All this
switching is invisible to the device driver, which just gets a completion
for the URB. Drivers that use streams must be able to handle URBs
completing in a different order than they were submitted to the endpoint.

This requires adding new API to set up xHCI data structures to support
multiple queues ("stream rings") per endpoint. Drivers will allocate a
number of stream IDs before enqueueing URBs to the bulk endpoints of the
device, and free the stream IDs in their disconnect function. See
Documentation/usb/bulk-streams.txt for details.

Much of the xHCI driver code assumes that endpoints only have one ring.
Now an endpoint can have one ring per enabled stream ID, so correct that
assumption. Use functions that translate the stream_id field in the URB
or the DMA address of a TRB into the correct stream ring.

Correct the polling loop to print out all enabled stream rings. Make the
URB cancellation routine find the correct stream ring if the URB has
stream_id set. Make sure the URB enqueueing routine does the same. Also
correct the code that handles stalled/halted endpoints.

Check that commands and registers that can take stream IDs handle them
properly. That includes ringing an endpoint doorbell, resetting a
stalled/halted endpoint, and setting a transfer ring dequeue pointer
(since that command can set the dequeue pointer in a stream context or an
endpoint context).

Correct the transfer event handler to translate a TRB DMA address into the
stream ring it was enqueued to. Make the code to allocate and prepare TD
structures adds the TD to the right td_list for the stream ring. Make
sure the code to give the first TRB in a TD to the hardware manipulates
the correct stream ring.

When an endpoint stalls, store the stream ID of the stream ring that
stalled in the xhci_virt_ep structure. Use that instead of the stream ID
in the URB, since an URB may be re-used after it is given back after a
non-control endpoint stall.

Add support for allocating streams for USB 3.0 bulk endpoints. See
Documentation/usb/bulk-streams.txt for more information about how and why
you would use streams.

When an endpoint has streams enabled, instead of having one ring where all
transfers are enqueued to the hardware, it has several rings. The ring
dequeue pointer in the endpoint context is changed to point to a "Stream
Context Array". This is basically an array of pointers to transfer rings,
one for each stream ID that the driver wants to use.

The Stream Context Array size must be a power of two, and host controllers
can place a limit on the size of the array (4 to 2^16 entries). These
two facts make calculating the size of the Stream Context Array and the
number of entries actually used by the driver a bit tricky.

Besides the Stream Context Array and rings for all the stream IDs, we need
one more data structure. The xHCI hardware will not tell us which stream
ID a transfer event was for, but it will give us the slot ID, endpoint
index, and physical address for the TRB that caused the event. For every
endpoint on a device, add a radix tree to map physical TRB addresses to
virtual segments within a stream ring.

Keep track of whether an endpoint is transitioning to using streams, and
don't enqueue any URBs while that's taking place. Refuse to transition an
endpoint to streams if there are already URBs enqueued for that endpoint.

We need to make sure that freeing streams does not fail, since a driver's
disconnect() function may attempt to do this, and it cannot fail.
Pre-allocate the command structure used to issue the Configure Endpoint
command, and reserve space on the command ring for each stream endpoint.
This may be a bit overkill, but it is permissible for the driver to
allocate all streams in one call and free them in multiple calls. (It is
not advised, however, since it is a waste of resources and time.)

Even with the memory and ring room pre-allocated, freeing streams can
still fail because the xHC rejects the configure endpoint command. It is
valid (by the xHCI 0.96 spec) to return a "Bandwidth Error" or a "Resource
Error" for a configure endpoint command. We should never see a Bandwidth
Error, since bulk endpoints do not effect the reserved bandwidth. The
host controller can still return a Resource Error, but it's improbable
since the xHC would be going from a more resource-intensive configuration
(streams) to a less resource-intensive configuration (no streams).

If the xHC returns a Resource Error, the endpoint will be stuck with
streams and will be unusable for drivers. It's an unavoidable consequence
of broken host controller hardware.

Includes bug fixes from the original patch, contributed by
John Youn <John.Youn@synopsys.com> and Andy Green <AGreen@PLXTech.com>

Allow the xHCI drivers (and any new USB 3.0 drivers) to parse the
SuperSpeed endpoint companion descriptor to find the maximum number of
bulk endpoint streams the endpoint supports. This is used to calculate
the maximum total number of streams the driver can allocate.

The generic USB serial code is ill-suited for high-speed USB wwan devices,
resulting in the option driver. However, other non-option devices may also
gain similar benefits from not using the generic code. Factorise out the
non-option specific code from the option driver and make it available to
other users.

This patch (as1366) replaces the private routines
usb_enable_autosuspend() and usb_disable_autosuspend() with calls to
the standard pm_runtime_allow() and pm_runtime_forbid() functions in
the runtime PM framework. They do the same thing.

This patch (as1364) avoids enabling remote wakeup by default on all
non-root-hub USB devices. Individual drivers or userspace will have
to enable it wherever it is needed, such as for keyboards or network
interfaces. Note: This affects only system sleep, not autosuspend.

External hubs will continue to relay wakeup requests received from
downstream through their upstream port, even when remote wakeup is not
enabled for the hub itself. Disabling remote wakeup on a hub merely
prevents it from generating wakeup requests in response to connect,
disconnect, and overcurrent events.

This patch (as1362) adjusts the way the USB autosuspend routines
handle remote-wakeup settings. They aren't supposed to use
device_may_wakeup(); that test is intended only for system sleep, not
runtime power management. Instead the code checks to see if any
interface drivers need remote wakeup; if they do then it is enabled,
provided the device is capable of it.

This patch (as1368) fixes a rather obscure bug in usbmon: When tracing
URBs sent by the scatter-gather library, it accesses the data buffers
while they are still mapped for DMA.

The solution is to move the mapping and unmapping out of the s-g
library and into the usual place in hcd.c. This requires the addition
of new URB flag bits to describe the kind of mapping needed, since we
have to call dma_map_sg() if the HCD supports native scatter-gather
operation and dma_map_page() if it doesn't. The nice thing about
having the new flags is that they simplify the testing for unmapping.

The patch removes the only caller of usb_buffer_[un]map_sg(), so those
functions are #if'ed out. A later patch will remove them entirely.

As a result of this change, urb->sg will be set in situations where
it wasn't set previously. Hence the xhci and whci drivers are
adjusted to test urb->num_sgs instead, which retains its original
meaning and is nonzero only when the HCD has to handle a scatterlist.

Finally, even when a submission error occurs we don't want to hand
URBs to usbmon before they are unmapped. The submission path is
rearranged so that map_urb_for_dma() is called only for non-root-hub
URBs and unmap_urb_for_dma() is called immediately after a submission
error. This simplifies the error handling.

Mass Storage Function (MSF) used the same descriptors for each
usb_function instance (meaning usb_function::descriptors of different
functions pointed to the same static area (the same was true for
usb_function::hs_descriptors)).

This would leads to problems if MSF were used in several USB
configurations with different interface and/or endpoint numbers.
Descriptors for all configurations would have interface/endpoint
numbers overwritten by the values valid for the last configuration.

This patch adds code that copies the descriptors each time MSF is
added to USB configuration (that is for each usb_function).

The composite framework allows gadgets with more than one function. This
can lead to situations where the configuration descriptor is larger than
the maximum of 512 bytes currently allowed by the composite framework.
This patch proposes to double that limit to 1024.